1. Field of the Invention
The present invention relates to a portable terminal. More particularly, the present invention relates to an antenna apparatus for a portable terminal.
2. Description of the Related Art
In general, a portable terminal is an appliance for providing wireless user-to-user communication or user-to-service provider communication through one or more mobile communication base stations. A user can be provided with various content including anything from communications and short message services to mobile banking, TV broadcasting, online gaming, and video-on-demand services.
A portable terminal has an antenna apparatus for securing an acceptable good signal-receiving percentage or a good communication quality, despite the radio frequency propagation environment varying due to its surroundings. Antenna apparatuses provided in portable terminals differ in specifications, such as length, depending on the frequency bands used by the service providers that the portable terminals operate with.
Such antenna apparatuses may be classified into an internal type and an external type. An internal type antenna is provided within a housing of a portable terminal. An external type antenna protrudes outwardly from the housing. Exemplary internal type antennas include a meander line antenna, a loop antenna, an inverted L antenna, and a planar inverted F antenna (PIFA). Exemplary external type antennas include a whip antenna having an antenna element such as a helical antenna received in an antenna housing and a retractable/extendible antenna element installed on a terminal housing.
FIG. 1 is a perspective view showing an antenna 100 for a portable terminal according to the prior art. As shown in FIG. 1, the conventional antenna apparatus 100 is formed as a planar inverted F antenna (hereinafter, referred to as “PIFA antenna”). The PIFA antenna comprises an antenna pattern 102, an antenna base 101 formed of a synthetic resin on which the antenna is configured, a printed circuit board 103, and a power feed point 121 and ground 123 which are provided for the purpose of feeding power.
However, the construction of a conventional internal type antenna apparatus, such as a PIFA antenna, is limited in improving a specific absorption ratio induced in a human body (hereinafter, referred to as “SAR”) because the current fed through the antenna apparatuses flows in one direction. In addition, the conventional internal type antenna deteriorates communications due to the generation of noise as well as the SAR.
Accordingly, there is a need for an improved internal type antenna apparatus that improves SAR and reduces noise so as to prevent deteriorated communications.